Silicone compositions curable by the reaction of a hydrosilyl group and an alkenyl group bonded to a silicon atom are known in the art.
However, cured products of such silicone compositions have no adhesion properties. Thus, for example, when such silicone compositions are injected into electric and electronic parts and cured therein, moisture easily penetrates through the gap formed between the parts and the cured silicone compositions, thus causing corrosion and deterioration in the insulation. It has therefore been attempted to solve the problems by incorporating adhesion-promoters into such compositions.
Compounds known in the art for providing adhesion properties to silicone rubber compositions include, for example, alkenyl group-containing alkoxysilanes (Japanese Patent Publication No. 36,255/72 and 34,362/79); epoxy compounds in combination with carboxylic anhydrides (Japanese Patent Application (Laid Open) No. 37,157/79); epoxy group-containing alkoxysilanes in combination with vinyl and hydroxyl group-containing siloxanes (Japanese Patent Application (Laid Open) No. 144,960/78); alkoxysilanes or siloxanes containing both epoxy groups and alkenyl groups (Japanese Patent Application (Laid Open) Nos. 24,258/77 and 147,657); hydrogensiloxanes containing oxirane groups bonded to the silicon atom (Japanese Patent Application (Laid Open) No. 240,360/87); acryloxyalkylalkoxysilanes used in combination with organic peroxides (Japanese Patent Application (Laid Open) No. 26,855/75); alkylenepropenoxysilanes or alkylenepropenoxysiloxanes (Japanese Patent Application (Laid Open) No. 3,460/75); and isocyanuric acids substituted with silanes or siloxanes (Japanese Patent Application (Laid Open) No. 137,355/82). It is disclosed in Japanese Patent Application (Laid Open) No. 94,068/75 that the ethylenically unsaturated group-containing isocyanurates, which have been used as an addition reaction inhibitor, also provide adhesion properties. However, with the recent development and rapid propagation of new substrate materials, particularly synthetic plastic materials, it is becoming increasingly difficult to improve the adhesion properties of silicone compositions using the adhesion-promoting compounds recited above. This is because substrate materials which have hitherto been made of easily-adhered to metal, such as aluminum, copper, nickel, etc. have been replaced in many applications by substrates made of hard-to-adhere to synthetic plastic materials. It has therefore been desired to develop silicone compositions which exhibit adhesion to a broad variety of synthetic plastic materials.
In Japanese Patent Application (Laid Open No. 48,853/79, it is disclosed that the compound having the following formula: ##STR1## is capable of imparting adhesion to silicone compositions. However, although silicone compositions incorporated with this compound exhibit good adhesion properties, the heat-resistant and moisture-resistant adhesive properties of cured products thereof are still insufficient.